---
license: mit
task_categories:
  - other
tags:
  - physics
  - fluid-dynamics
  - turbulence
  - simulation
  - vtk
pretty_name: 3D Driven Turbulence Simulation (128³)
size_categories:
  - 10G<n<100G
configs:
  - config_name: default
    data_files:
      - files_index.csv
---

# NS Simulation Dataset — 3D Driven Turbulence (128³)

## Overview

This dataset contains output from a 3D isothermal hydrodynamic driven turbulence simulation run with [AthenaK](https://github.com/PrincetonUniversity/athenak). The simulation models subsonic turbulence driven on large scales in a periodic box.

## Simulation Parameters

| Parameter | Value |
|---|---|
| Code | AthenaK |
| Problem | 3D driven turbulence |
| Grid resolution | 128 × 128 × 128 |
| Domain | [-0.5, 0.5]³ (unit box) |
| Boundary conditions | Periodic (all faces) |
| EOS | Isothermal |
| Isothermal sound speed | 5.0 |
| Time integrator | RK2 |
| CFL number | 0.3 |
| Spatial reconstruction | PLM |
| Riemann solver | HLLE |

## Turbulence Driving

| Parameter | Value |
|---|---|
| Driving type | Driven (continuously forced) |
| Energy injection rate (`dedt`) | 1×10⁻⁴ |
| Correlation time (`tcorr`) | 5.0 |
| Driving wavenumber range | nlow=1, nhigh=3 (peak at n=2) |
| Spectral form | Parabolic |
| Driving mode | Purely solenoidal (sol_fraction=1.0) |

## Files

- **Format:** Legacy VTK binary (`DATASET STRUCTURED_POINTS`)
- **Naming:** `Turb.hydro_w.NNNNN.vtk` where `NNNNN` is the output index
- **Total files:** 1001 snapshots (indices 18903–19903)
- **Time range:** t ≈ 189.03 to 199.03 (output cadence Δt = 0.01)
- **Grid size per file:** 128³ = 2,097,152 cells

## Data Fields (per file)

Each VTK file contains the following cell-centred scalar fields:

| Field name | Description |
|---|---|
| `dens` | Mass density ρ |
| `velx` | Velocity component v_x |
| `vely` | Velocity component v_y |
| `velz` | Velocity component v_z |
| `s_00` | Passive scalar (tracer) |

## Reading the Data

The files are standard VTK legacy binary format and can be read with [ParaView](https://www.paraview.org/), [VisIt](https://visit-dav.github.io/visit-website/), or Python via `vtk` or `pyvista`:

```python
import pyvista as pv

mesh = pv.read("Turb.hydro_w.18903.vtk")
density = mesh["dens"].reshape(128, 128, 128)
velx    = mesh["velx"].reshape(128, 128, 128)
```